There’s something silly about the furious debate in Washington over Susan Rice and her suitability to become Secretary of State. Republicans are obsessed with the way Rice publicly parroted CIA talking points about Benghazi when she toured the Sunday talk shows a few days after the deadly terrorist attack there. But they don’t have much to say otherwise about her qualifications for the job.

On second thought, maybe that’s fitting. After all, the job of Secretary of State isn’t what it used to be. Indeed, Rice’s dutiful on-message performance might actually be evidence for why she’d be good at it.

For decades, the Secretary of State tended to be as much a policy mastermind as a foreign diplomat. A string of Cold War Secretaries of State were visionary figures with huge policymaking influence. George Marshall oversaw the post–World War II reconstruction of Europe. Dean Acheson convinced Harry Truman to go to war in Korea. John Foster Dulles propounded the theory of brinksmanship with the Soviets. Henry Kissinger speaks for himself.

Since the Cold War’s end, the corner office at Foggy Bottom has been a much less consequential place. There have been some big moments: James Baker assembled the 1991 Gulf War’s international coalition. Warren Christopher (thanks to Richard Holbrooke) oversaw the hard-won 1995 Dayton accord that ended the Bosnian war. But with the simple and clarifying threat of the Soviets gone, Foggy Bottom grand strategy has been edged out by crisis management and muddling through an increasingly complex and unruly world.

Consider the job’s past few occupants. Madeleine Albright did a fine job in Bill Clinton’s second term but had no signature achievement. Ditto for George W. Bush’s two Secretaries: Colin Powell was marginalized by Dick Cheney and Donald Rumsfeld, and is best remembered for peddling flawed Iraq WMD intelligence to the United Nations. (Powell protests that he was just passing on talking points supplied by the intelligence community. Sound familiar?) Condoleezza Rice peddled Bush’s democracy agenda with mixed results and made a failed effort to jump-start the Middle East peace process.

Hillary Clinton generally wins glowing reviews for her tenure. But she has left light fingerprints on the U.S.’s post-Bush foreign policy. She initially outsourced Middle East peace and Afghanistan-Pakistan policy to George Mitchell and Holbrooke, respectively; both struck out. The Russia “reset” that she kicked off with much fanfare soon fizzled. President Obama has taken the lead on the U.S.’s public response to the Arab Spring. Clinton has scored no surprise diplomatic breakthroughs.

Yes, she was crucial to building the international coalition behind NATO’s Libya intervention. She has worked hard to unify the Syrian opposition. She has personally defended the U.S. against Pakistani hostility. And she has spent long hours in obscure places advancing the U.S.’s strategic pivot to Asia.

But Clinton’s tenure underscores the institutional limits of her job in the modern era. One limit is the growing role of the White House, with its expanded national security apparatus, in the making of foreign policy. The West Wing drives U.S. policy toward Iran and Israel. Clinton’s Syria diplomacy can only achieve so much as long as Obama resists a U.S. entanglement there. And the military and the CIA, meanwhile, take the lead in hot spots like Afghanistan, Yemen and Pakistan. (The last U.S. ambassador to Islamabad recently left in frustration, allegedly after complaining about the primacy of drone strikes over diplomacy.) And on one recent trip to China, Clinton spotlighted geopolitical reality by bringing along Treasury Secretary Tim Geithner, who may be at least as influential in Beijing.

Clinton has many admirers who insist she has been a historically significant Secretary but that her achievements may be hard to measure in conventional ways. “I think Secretary Clinton has been a truly visionary Secretary of State,” Anne-Marie Slaughter, who was a senior deputy at Clinton’s State Department until early 2011, told me in November. “It’s a vision that is much more about development, much more about reaching out to people — all the social-media stuff. She has innovated across that board in ways that are not always visible to people.”

Promoting American values and ideas around the world is no small priority, and Clinton deserves credit for that (even if she has occasionally trimmed her sails on human rights). She has also done heroic work advancing the welfare of women internationally. But this more subtle approach underscores the new limits of the State Department and the way Foggy Bottom shapes U.S. foreign policy mainly at the margins. The days of the policy visionary are long gone. Apart from providing counsel at the Cabinet table, there’s little room for independent thought or action. The modern Secretary of State’s mission is to be a high-profile envoy and spokesperson — a vessel for, well, American talking points. And in that sense, even Susan Rice’s critics have to admit that she’s qualified.